1. Field of the Invention
The invention concerns a method and article that provides a test for distinguishing cosmetic sticks containing water.
2. The Related Art
Cosmetic sticks require stiffening agents to render them hard. Waxes are classic stiffening agents, especially in lipsticks. As a consequence of being hydrophobic, wax formulations generally exclude water as a co-ingredient. For instance, most commercial lipsticks are devoid of any water.
Recent advances in cosmetic stick emulsification chemistry has achieved lipsticks incorporating water in amounts up to about 25%. See for instance a co-pending application Ser. No. 558,140, filed Jul. 25, 1990 (Dunphy et al). Incorporation of water into a lipstick has also been proposed in JP-A-61/83110 (Konuki) which provides for water-soluble substances to be compounded within an aqueous phase of the stick, this phase being homogeneously and stably dispersed within the waxy hydrophobic phase.
Certain problems arise with this relatively new technology. Water has a tendency to evaporate from the product, especially under conditions of prolonged storage at relatively elevated temperatures. A test would be desirable to evaluate this loss of moisture.
Another problem of the new moisture-containing lipstick technology is that a method would be desirable for demonstrating differences between traditional hydrophobic sticks and those incorporating moisture. A simple point-of-sale demonstration technique would be quite helpful in distinguishing these commercially unusual cosmetic sticks.
Accordingly it is an object of the present invention to provide a method for distinguishing moisture-containing sticks, especially lipsticks, which is simple and inexpensive to perform.
Another object of the present invention is to provide a test article in conjunction with the test method for demonstrating distinctiveness of moisture-containing cosmetic sticks, especially lipsticks.
These and other objects of the present invention will become more readily apparent through consideration of the following summary, detailed description and example which follow.